In a wireless signal transmit device, one key factor that affects communication quality is transmit signal distortion that is generated because a power amplifier (PA, Power Amplifier) operates in a non-linear area of the power amplifier. Currently, a digital predistortion (Digital Predistortion, DPD) technology is a common method for resolving a problem of PA distortion. The method can improve PA efficiency by reducing distortion generated when the PA runs in the non-linear area of the PA.
In a massive multiple-input multiple-output technology (Massive multiple-input multiple-output, Massive MIMO) application scenario, a quantity of transmit channels of a transmit device increases, and a digital predistortion processor and a feedback link need to be disposed for each transmit channel if a conventional digital predistortion apparatus is still used. Consequently, costs and link complexity of the transmit device are increased dramatically. In a current multichannel digital predistortion processing solution, digital predistortion training and processing need to be performed on a plurality of channels by turns if quantities of digital predistortion processors and feedback links are decreased. A larger quantity of channels results in lower digital predistortion processing efficiency. Consequently, a calibration implementation requirement cannot be met, and system performance is affected.
Therefore, a multi-transmit-channel digital predistortion calibration method and apparatus are required, to reduce implementation costs and complexity of the transmit device, ensure output linearity and efficiency of a multichannel power amplifier, and improve the system performance.